At a glance, there don’t appear to be many new features in the second beta of iOS 17.2 — with the exception of Spatial Video recording for Apple Vision Pro.
Settings toggle in iOS 17.2 beta 2 for Spatial Video recording
One of the features of the Apple Vision Pro is that it includes Apple’s first three-dimensional camera, capable of taking spatial photographs and videos that can be viewed via the headset. Apple promised the feature would arrive “later” for iPhone 15 Pro, and the first vestiges of it are available in iOS 17.2 beta 2.